Building a custom builder
Cloud Build uses a container image for each build step, which provides flexibility to essentially execute whatever binary or commands your build requires. Another pattern is where you build a custom builder image consisting of all the necessary build binaries required by the team. This can reduce complexity by having only one image to be used in build steps, but also only one image to be maintained.
Let’s start with an example where your build needs access to a few Google Cloud resources such as gcloud and gsutil, but you would still like a few more for your overall builds such as terraform, kustomize, and skaffold. While the base image provides the first two, we would have to either use the available community builder images for each tool (https://github.com/GoogleCloudPlatform/cloud-builders-community), build a new custom image for each tool, or a single image that the team can maintain with the latter three.
We start with a Dockerfile that...